Thanks man.. If anyone else is interested quake players are 56 units high whilst half-life / Ff players are 72. If my math is correct scaling a quake map by a factor of 1.285 ( I used 1.3) will make the proportions right for Ff. but be warned only do the scaling just before each compile and keep a regular size working copy as scaling by odd numbers throws all the brushes off grid.

Yeah you would make everything so much easier for yourself if you just rounded up or down and kept everything on grid the whole time. Hammer can be a nightmare when you start to do goofy stuff. I'd suggest rounding up or down, and just scaling it to what seems comfortable. It doesn't have to be perfectly to scale. Take phantom for example, very comfortable, not a 1:1 port.

The 1 unit : 1 inch (or 12 unit = 1 foot) scale applies only to Human Character models (for reasons only known to Valve :/), not to Map geometry. For evidence see the Dev/ textures for doors, etc, in Hammer. The Hammer grid-snap increments also lend themselves to thinking of dimensions in terms of feet rather than inches, as they are simple multiples (or fractions) of 16 units. --Beeswax 12:19, 31 Jan 2008 (PST)

Just because the hammer grid has a major division every 16 inches doesn't change the scale.

If you make a 1"x1"x1" model and put 16 of them in a row, they'll line up perfectly with the hammer grid.

You have to look at the history of Hammer to understand why they used a base 2 grid to describe the world. Worldcraft as it was originally called, was originally a Quake map editor. Half-Life and later Source were more bolted on hacks cobbled together into Hammer.

It's easier to work with base 2 numbers in memory over some arbitrary definition like 12, 24, 36, etc. You end up having to allocate more memory to do such things, and in 1996 memory was expensive and computers were much slower so you had to do everything possible to speed things up. The base inch unit hasn't changed, it's just the grid isn't going to align to feet, yards or miles.

Hammer could be recoded to allow changing how the grid is defined, but you'd also have to change the terrible compile tools because I doubt they'd tolerate it. The current compile tools barely work as is and only make an approximation of the level you design because the precision is so bad.